Money supply measures how much money like instruments circulate in an economy. The labels M1 and M2 are the US (and many textbook) aggregates most people meet first. M1 is the narrow, highly liquid core. M2 is broader and includes near money such as many savings deposits. Definitions have changed over time, especially in the United States after 2020, so reading the fine print on FRED or Federal Reserve H.6 releases matters. This explainer sticks to concepts, UK parallels, and common myths. Educational only; not investment advice.
Why money aggregates exist
Cash and chequeable deposits are money in everyday use: they settle payments at par. Other assets are close substitutes. Statistical agencies therefore publish layered aggregates. Narrow measures track transaction balances. Broad measures add instruments that can be converted into transactions balances quickly with little price risk. The goal is a consistent time series for research and teaching, not a single “correct” money number for every purpose.
Modern monetary policy in the US and UK focuses more on interest rates, inflation forecasts, and credit conditions than on hitting a money growth target. Money aggregates still help describe balance sheet shifts, banking behaviour, and historical episodes. See the monetary and fiscal policy pillar and quantitative easing.
M1 versus M2 in the United States
Exact component lists evolve, but the teaching contrast is stable:
- M1 emphasises currency in circulation and highly liquid deposits used for payments (such as chequeable deposits and, under current US definitions, certain other liquid transferrable deposits). Think “spendable now.”
- M2 includes M1 plus less immediately transactional but still liquid retail balances, such as many savings deposits and small time deposits, plus retail money market funds (subject to the official definition in force).
FRED mirrors Federal Reserve Board money stock series. When you open a chart, check the notes for definition breaks. A famous US break around May 2020 reclassified many savings deposits into M1, which made M1 jump for statistical reasons even when households did not suddenly “create” cash in the street sense.
UK framing: notes, deposits, and broad money
The United Kingdom does not lean on the M1/M2 classroom labels in the same public way. Bank of England and ONS discussions often emphasise notes and coin, retail deposits, and broad money measures (commonly discussed in M4 style families historically, with retail and wholesale splits). The economic idea is the same: layer liquidity from cash like instruments out to broader deposits. When comparing US M2 growth headlines with UK broad money growth, align definitions before drawing strong conclusions.
Money is a spectrum of liquidity. M1 and M2 are convenient cuts of that spectrum, not mystical switches that turn inflation on or off by themselves.
Worked example (illustrative)
Imagine a household moves £10,000 from a savings style balance into a current account ready for spending. Depending on how the country’s aggregates are defined, that shift can raise a narrow money measure while leaving a broad measure little changed, because the funds never left the banking system. Separately, if banks expand lending and create new deposits, broad money can rise even without anyone “printing cash” at home. These stories are teaching sketches. For live figures use the Fed H.6 release via FRED or Bank of England money and credit publications.
Money growth and inflation: careful links
Over long horizons, sustained money growth far ahead of real output growth has often accompanied higher inflation in historical samples. In the short run, velocity (how often money turns over), credit conditions, supply shocks, and anchored expectations can break any simple month to month link. After large QE programmes, central bank reserves and broad money can move in ways that confuse slogans. Pair money charts with inflation measures from CPI versus PCE and core versus headline inflation, and with real activity from the GDP pillar.
Common myths
- Myth: M2 is a precise inflation forecast. It is one indicator among many. Velocity and credit matter.
- Myth: a definition break is the same as an economic boom in money. Read release notes. The 2020 US M1 reclassification is the classic cautionary tale.
- Myth: cash printing is the only way money grows. Bank lending and deposit creation are central in modern systems.
- Myth: UK and US labels are interchangeable. Component lists and publicity conventions differ.
How to read the series
Prefer official Fed H.6 and Bank of England statistical releases, or FRED series with clear documentation. Note seasonally adjusted versus not. Compare year over year growth rates when levels are dominated by one off level shifts. Related tools and guides: CPI data guide, sources directory, US snapshot, UK snapshot. Glossary anchors such as quantitative easing and policy rate help connect aggregates to policy instruments.
One careful habit: when a social media chart shows an M2 spike, ask whether a definition changed, whether the axis is levels or growth, and which inflation and credit series sit beside it.